ExploreUICollectionView/ViewController.m

//
//  ViewController.m
//  ExploreUICollectionView
//
//  Created by Michael Lehman on 1/6/13.
//  Copyright (c) 2013 Developer Extraordinaire. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (strong, nonatomic) IBOutlet UICollectionView *myCollectionView;
@property (nonatomic, strong) NSMutableArray *cellData;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.myCollectionView.delegate = self;
    self.myCollectionView.dataSource = self;

    self.cellData = [[NSMutableArray alloc]init];

    for(int i=0; i < 100; i++)
    {
        [self.cellData addObject:[NSString stringWithFormat:@"#%d", i+1]];
    }

    UINib *cellNib = [UINib nibWithNibName:@"CVCell"
                                    bundle:nil];
    [self.myCollectionView registerNib:cellNib
            forCellWithReuseIdentifier:@"CVCell"];

    UICollectionViewFlowLayout *layout =
    [[UICollectionViewFlowLayout alloc] init];

    [layout setItemSize:CGSizeMake(100, 100)];
    [layout setScrollDirection:UICollectionViewScrollDirectionVertical];

    [self.myCollectionView setCollectionViewLayout:layout];
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"CVCell";
    UICollectionViewCell *cell =
    [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier
                                              forIndexPath:indexPath];

    UILabel *cellTitle = (UILabel *)[cell viewWithTag:1];

    cellTitle.text = [self.cellData objectAtIndex:indexPath.row];
    return cell;
}

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [self.cellData count];
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    UILabel *cellTitle = (UILabel *)[cell viewWithTag:1];
    NSLog(@"You selected cell: %@", cellTitle.text);
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end